The present invention relates to optical systems for delivering light from a light source to a destination such as a detector, and more particularly, to such systems that are adapted to reduce back reflection from the destination back to the light source.
Optical technology is used in a wide variety of fields including telecommunications, computers, and medical fields. In many applications, a light guide—such as an optical fiber—is used to deliver a light signal from a light source to a light detector. An important consideration in many of these systems is the optical coupling performance between the light source, the optical fiber, and the light detector. In many cases, the optical fiber is simply “butt-coupled” to the light source and/or light detector. While this may be adequate for some applications, it has been found that in some cases, some of the light that is delivered to the light detector is reflected by the light detector back into the optical fiber, and in some cases, back into the light source. Such back reflection can in some cases create significant noise. For example, it has been found that such back reflections can create optical feedback in some light sources, which can produce increased jitter and increased Reflective Intensity Noise (RIN). Back reflections can also cause interferometric noise in some light sources by converting some light source phase noise into light source intensity noise. For optical communications systems, this can result in increased bit error rates (BER), and reduced performance. For other applications, such as computer and medical applications, this noise can result in reduced system performance and/or reduced reliability.